The video captured on a mobile phone showed a bag burning in an overhead compartment before it was put out by a quick-thinking air stewardess.

The flight attendant managed to successfully put out the fire when she threw a bottle of water into the flames. A passenger made sure the fire was properly extinguished by dousing the bag with another bottle of liquid﻿.

Fortunately, the plane was still grounded when the incident happened, but it caused a three-hour delay

China Southern Airlines released a statement on the popular Chinese microblogging site Weibo, saying that passengers were boarding flight CZ3539 at Guangzhou Baiyun International Airport ﻿when a passenger’s bag started emitting smoke and burst into flames.

According to South China Morning Post, the airline praised the flight attendant's quick reaction, “Our colleague reacted to the fire in a timely and appropriate way."

The owner of the power bank was taken in by the police for further investigation while the rest of the passengers were placed on a replacement aircraft, which departed almost three hours later than the scheduled departure time.

Early investigations revealed that the power bank was not in use when it caught fire.

What’s the SOP for carrying power banks on commercial flights?

According to the International Civil Aviation Organization, spare batteries containing lithium-ion batteries (such as a power bank or external battery pack) are banned from checking in. They are, however, usually allowed in hand-carry luggage within permissible limits.

Back in January, an individual from Twitter asked AirAsia if power banks are allowed on the plane or not. Here's their response:

Hi Raunak, it is allowed up to 32,000 mAh per guest and it must be hand carry. Please note that powerbank is strictly not allowed to be checked in. Thanks - Ed